TY - Generic T1 - Earth's Magnetic Field Migration and Its Effects on HF Propagation T2 - HamSCI Workshop 2024 Y1 - 2024 A1 - Philip J. Erickson A1 - William Liles AB -

Propagation of radio waves in Earth's ionosphere and atmosphere critically depends on the strength and orientation of Earth's background magnetic field, due to the fact that electrons move much more readily along field lines than across them.  The background magnetic field evolves continuously, driven by currents and other processes inside the planet's molten core.  In particular, since 1990, the north magnetic pole has been migrating at an increased speed relative to its rate over most of the past century, and now moves more than 40 km/year.  However, the south magnetic pole migration is considerably slower.  The combination of these two effects has caused the global configuration of the geomagnetic field to change significantly.  We will describe the sustained drift of magnetic field line locations over the last 40 years, with an emphasis on mid-latitudes where a large number of amateur radio operations take place.  We will then provide estimates of induced changes in HF propagation over that time, using multiple models, and draw conclusions regarding the general climatology of propagation in various well used bands.

JF - HamSCI Workshop 2024 PB - HamSCI CY - Cleveland, OH ER - TY - Generic T1 - Possible Drivers of Large Scale Traveling Ionospheric Disturbances by Analysis of Aggregated Ham Radio Contacts T2 - HamSCI Workshop 2024 Y1 - 2024 A1 - Diego Sanchez A1 - Mary Lou West A1 - Nathaniel A. Frissell A1 - Gareth W. Perry A1 - William D. Engelke A1 - Robert B. Gerzoff A1 - Philip J. Erickson A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker A1 - V. Lynn Harvey AB -

Large Scale Traveling Ionospheric Disturbances (LSTIDs) are quasiperiodic electron density perturbations of the F region ionosphere that have periods of 30 min to over 180 min, wavelengths of over 1000 km, and velocities of 150 to 1000 m/s. These are seen as long slow oscillations in the bottom side of the ionosphere in data from ham radio contacts at 20 meters wavelength on roughly a third of the days in a year. They might be triggered by electromagnetic forces from above, and/or by mechanical pressures from below. The explosion of the Tonga volcano on January 15, 2022 revealed that such a LSTID could be triggered by a violent updraft from the Earth’s surface into the stratosphere and then detected in the ionosphere over the United States nine hours later. We consider other possible drivers such as the auroral electrojet, the polar vortex, thunderstorms, zonal wind speeds, gravity wave variances, and their time derivatives in 2017.

JF - HamSCI Workshop 2024 PB - HamSCI CY - Cleveland, OH ER - TY - Generic T1 - Climatology of Large Scale Traveling Ionospheric Disturbances Observed with Amateur Radio Networks T2 - HamSCI Workshop 2023 Y1 - 2023 A1 - Diego Sanchez A1 - Mary Lou West A1 - Bob Gerzoff A1 - Gareth W. Perry A1 - Nathaniel A. Frissell A1 - William D. Engelke A1 - Philip J. Erickson AB -

A new climatology of Large Scale Traveling Ionospheric Disturbances (LSTIDs) has been observed from ham radio data in 2017. LSTIDs are quasiperiodic electron density perturbations of the F region ionosphere. LSTIDs have periods of 30 min to over 180 min, wavelengths of over 1000 km, and velocities of over 1400 km/hr. In this paper, we show a climatology of observed LSTID events using data from the Reverse Beacon Network (RBN), Weak Signal Propagation Network (WSPRNet), and PSKReporter amateur radio networks. This climatology was performed twice and was cross examined between two members of the research team. Results show that most of the observed LSTIDs occurred during the winter months with a decline towards the summer, with the exception of a spike in June. This paper provides additional insight into the seasonal trends of LSTIDs and provides additional knowledge that will help in the pursuit of what is causing this phenomenon.

JF - HamSCI Workshop 2023 PB - HamSCI CY - Scranton, PA ER - TY - Generic T1 - Low-Cost Low-Power Ionosonde T2 - HamSCI Workshop 2023 Y1 - 2023 A1 - Gerard N. Piccini A1 - Robert W. McGwier A1 - Robert A. Spalletta A1 - Majid Mokhtari A1 - Nathaniel A. Frissell A1 - Philip J. Erickson AB -

Ionosondes are a type of radar used to gather data about the height of the ionosphere. Typically, these systems can easily cost thousands of dollars and demand a lot of power. Using newer software defined radio technology, our goal is to develop a low cost, low power ionosonde.

JF - HamSCI Workshop 2023 PB - HamSCI CY - Scranton, PA ER - TY - Generic T1 - Measuring Daily Ionospheric Variability and the 2023 and 2024 Solar Eclipse Ionospheric Impacts Using HamSCI HF Doppler Shift Receivers T2 - HamSCI Workshop 2023 Y1 - 2023 A1 - Rachel Boedicker A1 - Nathaniel Frissell A1 - Kristina Collins A1 - John Gibbons A1 - David Kazdan A1 - Philip J. Erickson AB -

This project will study ionospheric variability across the continental United States (CONUS) generated by dawn/dusk transitions and two solar eclipses occurring in 2023 and 2024. Dawn and dusk produce a complex response in observed ionospheric variability that is still not completely understood. A network of Global Navigation Satellite System (GNSS) stabilized/synchronized high frequency (HF) receivers known as Grapes will be used for the study. Thirty Grape receivers will be deployed throughout North America to optimize the study of the ionospheric impacts simultaneously received from two locations. Additional stations will be funded by the HamSCI amateur radio community. This project will generate observations to answer the scientific questions: (1) How do dawn and dusk ionospheric variability vary with local time, season, latitude, longitude, frequency, distance, and direction from the transmitter? (2) Is eclipse ionospheric response symmetric with regard to the onset and recovery timing? (3) How similar is the eclipse to the daily dawn and dusk terminator passage? (4) Would multipath HF mode-splitting in the post-eclipse interval be similar to dawn events? (5) Would the response be different for two eclipses?

This project is part of the Ham Radio Science Citizen Investigation (HamSCI) program and will be open to volunteers who want to field instruments and contribute to scientific analysis and discussion. This project will also establish a new network of DASI instruments that, due to its low cost and operation by volunteers, has the potential to provide measurements for years to come. This project will support students (undergraduate, MS and Ph.D.).

JF - HamSCI Workshop 2023 PB - HamSCI CY - Scranton, PA ER - TY - Generic T1 - Medium Scale Traveling Ionospheric Disturbances and their Connection to the Lower and Middle Atmosphere T2 - HamSCI Workshop 2023 Y1 - 2023 A1 - Nathaniel A. Frissell A1 - Francis Tholley A1 - V. Lynn Harvey A1 - Sophie R. Phillips A1 - Katrina Bossert A1 - Sevag Derghazarian A1 - Larisa Goncharenko A1 - Richard Collins A1 - Mary Lou West A1 - Diego F. Sanchez A1 - Gareth W. Perry A1 - Robert B. Gerzoff A1 - Philip J. Erickson A1 - William D. Engelke A1 - Nicholas Callahan A1 - Lucas Underbakke A1 - Travis Atkison A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker JF - HamSCI Workshop 2023 PB - HamSCI CY - Scranton, PA ER - TY - Generic T1 - Climatology of Large Scale Traveling Ionospheric Disturbances Observed by HamSCI Amateur Radio with Connections to Geospace and Neutral Atmospheric Sources T2 - HamSCI Workshop 2022 Y1 - 2022 A1 - Diego S. Sanchez A1 - Nathaniel A. Frissell A1 - Gareth W. Perry A1 - V. Lynn Harvey A1 - William D. Engelke A1 - Anthea Coster A1 - Philip J. Erickson A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker AB -

Traveling Ionospheric Disturbances (TIDs) are propagating variations of F-region ionospheric electron densities that can affect the range and quality of High Frequency (HF, 3-30 MHz) radio communications. TIDs create concavities in the ionospheric electron density profile that move horizontally with the TID and cause skip-distance focusing effects for high frequency radio signals propagating through the ionosphere. TIDs are of great interest scientifically because they are often associated with neutral Atmospheric Gravity Waves (AGWs) and can be used to advance understanding of atmosphere-ionosphere coupling. Large scale TIDs (LSTIDs) have periods of 30-180 min, horizontal phase velocities of 100 - 250 m/s, and horizontal wavelengths of over 1000 km and are believed to be generated either by geomagnetic activity or lower atmospheric sources. The signature of this phenomena is manifest as quasi-periodic variations in contact ranges in HF amateur radio communication reports recorded by automated monitoring systems such as the Weak Signal Propagation Reporting Network (WSPRNet) and the Reverse Beacon Network (RBN). Current amateur radio observations are only able to detect LSTIDs. In this study, we present a climatology of LSTID activity using RBN and WSPRNet observations on the 1.8, 3.5, 7, 14, 21, and 28 MHz amateur radio bands from 2017. Results will be organized as a function observation frequency, longitudinal sector (North America and Europe), season, and geomagnetic activity level. Connections to geospace are explored via SYM-H and Auroral Electrojet indexes, while neutral atmospheric sources are explored using NASA’s Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2).

JF - HamSCI Workshop 2022 PB - HamSCI CY - Huntsville, AL ER - TY - Generic T1 - Detecting Large Scale Traveling Ionospheric Disturbances using Feature Recognition and Amateur Radio Data T2 - HamSCI Workshop 2022 Y1 - 2022 A1 - William D. Engelke A1 - Nathaniel A. Frissell A1 - Travis Atkison A1 - Philip J. Erickson A1 - Francis Tholley AB -

A Large-Scale Transient Ionospheric Disturbance (LSTID) is a traveling perturbation in ionosphere electron density with a horizontal wavelength of approximately 1000 km and a period between 30 to 180 minutes. These can be detected by SuperDARN HF radar and GNSS Total Electron Content measurements. Recently it has been discovered that these can also be detected in amateur (ham) radio signal reports, which are now being generated in vast numbers by operators world-wide. A machine-learning technique was developed to find patterns in these data that indicate the presence of LSTIDs using an object detection technique.

JF - HamSCI Workshop 2022 PB - HamSCI CY - Huntsville, AL ER - TY - CONF T1 - HamSCI Campaign Co-Design (Panel Discussion) T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - Kristina V. Collins A1 - Nathaniel A. Frissell A1 - Philip J. Erickson A1 - Laura Brandt A1 - Elizabeth MacDonald A1 - Michael Black A1 - Gareth Perry JF - HamSCI Workshop 2021 PB - HamSCI CY - Virtual ER - TY - CONF T1 - HamSCI Personal Space Weather: Architecture and Applications to Radio Astronomy T2 - Annual (Summer) Eastern Conference Y1 - 2021 A1 - Nathaniel A. Frissell A1 - Scott H. Cowling A1 - Thomas C. McDermott A1 - John Ackermann A1 - David Typinski A1 - William D. Engelke A1 - David R. Larsen A1 - David G. McGaw A1 - Hyomin Kim A1 - David M. Witten, II A1 - Julius M. Madey A1 - Kristina V. Collins A1 - John C. Gibbons A1 - David Kazdan A1 - Aidan Montare A1 - Dev Raj Joshi A1 - Veronica I. Romanek A1 - Cuong D. Nguyen A1 - Stephen A. Cerwin A1 - William Liles A1 - Jonathan D. Rizzo A1 - Ethan S. Miller A1 - Juha Vierinen A1 - Philip J. Erickson A1 - Mary Lou West AB -

The Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS) project is a citizen science initiative to develop a new modular set of ground-based instrumentation for the purpose of studying the structure and dynamics of the terrestrial ionosphere, as well as the larger, coupled geospace system. PSWS system instrumentation includes radio receivers sensitive to frequencies ranging from the very low frequency (VLF) through very high frequency (VHF) bands, a Global Navigation Satellite System (GNSS) receiver to provide Total Electron Content (TEC) measurements and serve as a precision time and frequency reference, and a ground magnetometer sensitive to ionospheric and geospace currents. Although the PSWS is designed primarily for space weather and space science, its modular and open design in both hardware and software allows for a variety of use cases. The core radio instrument of the PSWS, the TangerineSDR, is a wideband, direct sampling 100~kHz to 60~MHz field programmable gate array (FPGA)-based software defined radio (SDR) receiver with direct applicability to radio astronomy. In this paper, we describe the PSWS and TangerineSDR architecture, show examples of how the TangerineSDR could be used to observe Jovian decametric emission, and discuss the applicability of the TangerineSDR to radio astronomy in general.

JF - Annual (Summer) Eastern Conference PB - Society of Amateur Radio Astronomers (SARA) CY - Virtual UR - https://rasdr.org/store/books/books/journals/proceedings-of-annual-conference ER - TY - CONF T1 - HamSCI Personal Space Weather Station (PSWS): Architecture and Current Status T2 - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) Y1 - 2021 A1 - Nathaniel A. Frissell A1 - Dev Joshi A1 - Veronica I. Romanek A1 - Kristina V. Collins A1 - Aidan Montare A1 - David Kazdan A1 - John Gibbons A1 - William D. Engelke A1 - Travis Atkison A1 - Hyomin Kim A1 - Scott H. Cowling A1 - Thomas C. McDermott A1 - John Ackermann A1 - David Witten A1 - Julius Madey A1 - H. Ward Silver A1 - William Liles A1 - Steven Cerwin A1 - Philip J. Erickson A1 - Ethan S. Miller A1 - Juha Vierinen AB -

Recent advances in geospace remote sensing have shown that large-scale distributed networks of ground-based sensors pay large dividends by providing a big picture view of phenomena that were previously observed only by point-measurements. While existing instrument networks provide excellent insight into ionospheric and space science, the system remains undersampled and more observations are needed to advance understanding. In an effort to generate these additional measurements, the Ham Radio Science Citizen Investigation (HamSCI, hamsci.org) is working with the Tucson Amateur Packet Radio Corporation (TAPR, tapr.org), an engineering organization comprised of volunteer amateur radio operators and engineers, to develop a network of Personal Space Weather Stations (PSWS). These instruments that will provide scientific-grade observations of signals-of-opportunity across the HF bands from volunteer citizen observers as part of the NSF Distributed Array of Small Instruments (DASI) program. A performance-driven PSWS design (~US$500) will be a modular, multi-instrument device that will consist of a dual-channel phase-locked 0.1-60 MHz software defined radio (SDR) receiver, a ground magnetometer with (~10 nT resolution and 1-sec cadence), and GPS/GNSS receiver to provide precision time stamping and serve as a GPS disciplined oscillator (GPSDO) to provide stability to the SDR receiver. A low-cost PSWS (< US$100) that measures Doppler shift of HF signals received from standards stations such as WWV (US) and CHU (Canada) and includes a magnetometer is also being developed. HF sounding algorithms making use of signals of opportunity will be developed for the SDR-based PSWS. All measurements will be collected into a central database for coordinated analysis and made available for public access.

JF - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) PB - CEDAR CY - Virtual ER - TY - CONF T1 - Observing Large Scale Traveling Ionospheric Disturbances using HamSCI Amateur Radio: Climatology with Connections to Geospace and Neutral Atmospheric Sources T2 - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) Y1 - 2021 A1 - Diego F. Sanchez A1 - Nathaniel A. Frissell A1 - Gareth W. Perry A1 - William D. Engelke A1 - Anthea Coster A1 - Philip J. Erickson A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker AB -

Large Scale Traveling lonospheric Disturbances (TIDs) are propagating variations in ionospheric electron densities that affect radio communications. LSTIDs create concavities in the ionospheric electron density profile that move horizontally with the LSTID and cause skip-distance focusing effects for high frequency (HF, 3-30 MHz) radio signals propagating through the ionosphere. This phenomena manifests as quasi-periodic variations in contact ranges in HF amateur radio communications recorded by automated monitoring systems such as RBN and WSPRNet. In this study, members of the Ham Radio Science Citizen Investigation (HamSCI) present a climatology of LSTID activity as well as using RBN and WSPRNet observations on the 1.8, 3.5, 7, 14, 21, and 28 MHz amateur radio bands from 2017. Results will be organized as a function observation frequency, longitudinal sector, season, and geomagnetic activity level. Connections to neutral atmospheric sources are also explored.

JF - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) PB - CEDAR CY - Virtual ER - TY - Generic T1 - Observing Traveling Ionospheric Disturbances using HamSCI Amateur Radio: Validation and Climatology T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - Diego F. Sanchez A1 - Nathaniel A. Frissell A1 - Gareth W. Perry A1 - William D. Engelke A1 - Anthea Coster A1 - Philip J. Erickson A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker AB -

Traveling lonospheric Disturbances (TIDs) are propagating variations in ionospheric electron densities that affect radio communications and can help with understanding energy transport throughout the coupled magnetosphere-ionosphere-neutral atmosphere system. Large scale TIDs (LSTIDs) have periods T\ \approx30-180\ min, horizontal phase velocities v_H\approx‍100-‍250 m/s, and horizontal wavelengths \lambda_H>1000 km and are believed to be generated either by geomagnetic activity or lower atmospheric sources. TIDs create concavities in the ionospheric electron density profile that move horizontally with the TID and cause skip-distance focusing effects for high frequency (HF, 3-30 MHz) radio signals propagating through the ionosphere. The signature of this phenomena is manifest as quasi-periodic variations in contact ranges in HF amateur radio communication reports recorded by automated monitoring systems such as the Weak Signal Propagation Reporting Network (WSPRNet) and the Reverse Beacon Network (RBN). First in this study, members of the Ham Radio Science Citizen Investigation (HamSCI) present a case study showing consistency in LSTID signatures in RBN and WSPRNet are also present in Super Dual Auroral Radar Network (SuperDARN), Global Navigation Satellite System (GNSS), and ionosonde measurements. Then, we present a climatology of LSTID activity as well as  using RBN and WSPRNet observations on the 1.8, 3.5, 7, 14, 21, and 28 MHz amateur radio bands from 2017. Results will be organized as a function observation frequency, longitudinal sector (North America and Europe), season, and geomagnetic activity level.

JF - HamSCI Workshop 2021 PB - HamSCI CY - Scranton, PA (Virtual) ER - TY - CONF T1 - Sources of Large Scale Traveling Ionospheric Disturbances Observed using HamSCI Amateur Radio, SuperDARN, and GNSS TEC T2 - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) Y1 - 2021 A1 - Nathaniel A. Frissell A1 - Diego F. Sanchez A1 - Gareth W. Perry A1 - Dev Joshi A1 - William D. Engelke A1 - Evan G. Thomas A1 - Anthea Coster A1 - Philip J. Erickson A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker AB -

Large Scale Traveling Ionospheric Disturbances (LSTIDs) are quasi-periodic variations in F region electron density with horizontal wavelengths > 1000 km and periods between 30 to 180 min. On 3 November 2017, LSTID signatures were detected in simultaneously over the continental United States in observations made by global High Frequency (HF) amateur (ham) radio observing networks and the Blackstone (BKS) SuperDARN radar. The amateur radio LSTIDs were observed on the 7 and 14 MHz amateur radio bands as changes in average propagation path length with time, while the LSTIDs were observed by SuperDARN as oscillations of average scatter range. LSTID period lengthened from T ~ 1.5 hr at 12 UT to T ~ 2.25 hr by 21 UT. The amateur radio and BKS SuperDARN radar observations corresponded with Global Navigation Satellite System differential Total Electron Content (GNSS dTEC) measurements. dTEC was used to estimate LSTID parameters: horizontal wavelength 1136 km, phase velocity 1280 km/hr, period 53 min, and propagation azimuth 167°. The LSTID signatures were observed throughout the day following ~400 to 800 nT surges in the Auroral Electrojet (AE) index. As a contrast, 16 May 2017 was identified as a period with significant amateur radio coverage but no LSTID signatures in spite of similar geomagnetic conditions and AE activity as the 3 November event. We hypothesize that atmospheric gravity wave (AGW) sources triggered by auroral electrojet intensifications and associated Joule heating are the source of the LSTIDs, and that seasonal neutral atmospheric conditions may play a role in preventing AGW propagation in May but not in November.

JF - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) PB - CEDAR CY - Virtual ER - TY - Generic T1 - Survey of ionospheric F2 region variability from the lower atmosphere: drivers and responses - Part 2 T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - Philip J. Erickson A1 - R. Carl Luetzelschwab AB -

Phil Erickson, W1PJE, will follow with a condensed summary of recent community research on the types of physical processes that produce F2 layer ionospheric variations from waves, heating, and other sources in the lower neutral atmosphere (space weather “from below”). Examples will include acoustic waves, gravity waves, planetary waves, TADs (traveling atmospheric disturbances), and their influence on TIDs (travelling ionospheric disturbances). Numerical estimates of the various forcing terms provide a useful gauge of the relative importance and impact of these processes. Phil will close by specifically focusing on estimates of the magnitude of electron density variations in the F2 region of the ionosphere due to earthquake effects. In particular, ionospheric density observations from sources such as the global satellite navigation system (GNSS) allow a quantitative, numerate discussion of earthquake drivers in both time and space dimensions as compared to other known lower atmosphere ionospheric variability drivers.  Phil will conclude with a discussion of the implications for earthquake associated HF propagation effects in the face of observed day-to-day ionospheric density variability.

JF - HamSCI Workshop 2021 PB - HamSCI CY - Scranton, PA (Virtual) ER - TY - Generic T1 - Survey of ionospheric F2 region variability from the lower atmosphere: drivers and responses - Part 1 T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - R. Carl Luetzelschwab A1 - Philip J. Erickson AB -

Carl Luetzelschwab, K9LA, will review the factors that cause the F2 region of the ionosphere to vary in the short-term, on day-to-day and even shorter time scales. These factors can directly affect amateur radio operators through their influence on electron density and therefore on HF propagation. Ionospheric variability drivers will be sorted into three broad categories: 1) solar radiation 2) geomagnetic activity and 3) meteorological sources (neutral atmosphere). Carl will also assess how much F2 ionospheric parameters vary in the short-term during both day and night, and he will also review the contribution of each of the factors to observed F2 region variability.

JF - HamSCI Workshop 2021 ER - TY - Generic T1 - Traveling ionospheric disturbances tracked through Doppler-shifted AM radio transmissions T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - Claire C. Trop A1 - James LaBelle A1 - Philip J. Erickson A1 - Shunrong Zhang A1 - David McGaw A1 - Terrence Kovacs AB -

A comprehensive understanding of the ionosphere is critical for many technologies, particularly those that rely on the propagation of radio waves. This study shows that traveling ionospheric disturbances (TIDs), dawn and dusk signal divergence (terminators), and spread F can be tracked and analyzed using clear channel AM radio transmissions and a set of geographically distributed receivers. Early attempts by our research group to track TIDs by AM radio signals reflected from the F region of the ionosphere generated results in conflict with those derived from GPS/TEC mapping methods [Chilcote et al., 2015]. This study seeks to resolve those conflicts with a more sophisticated array of receivers spread throughout the northeastern United States. Specifically, the receivers form a ring around an 810 kHz AM radio station in Schenectady, New York. A minimum of four receivers have been operational from 3/19/20 to the present and Doppler-shifted signals, attributed to TID events, have been consistently visible across several radio channels with frequencies between 800 to 1600kHz. We have focused our study thus far on the terminator signals which appear to be consistent with photochemistry effects and on TID wave characteristic analysis. We have collected a set of exceptional TID events over the past nine months and have correlated our calculated wave characteristics with the data from GNSS TEC, digisonde, and SuperDARN in general finding good agreement between our technique and these established methods. While our study still seeks to clarify discrepancies in our data similar to those seen by Chilcote in the original study, the consistency with which our data typically agrees with other methods supports the validity of using AM radio transmissions to track TIDs in addition to other ionospheric phenomena such as the terminator. 

Reference: Chilcote, M., et al. (2015), Detection of traveling ionospheric disturbances by medium-frequency Doppler sounding using AM radio transmissions, Radio Sci., 50, doi:10.1002/2014RS005617.

JF - HamSCI Workshop 2021 PB - HamSCI CY - Scranton, PA (Virtual) ER - TY - CONF T1 - HamSCI: Space Weather Operational Resources and Needs of the Amateur Radio Community T2 - American Meteorological Society Annual Meeting Y1 - 2020 A1 - Nathaniel A. Frissell A1 - Philip J. Erickson A1 - Ethan S. Miller A1 - William Liles A1 - H. Ward Silver A1 - R. Carl Luetzelschwab A1 - Tamitha Skov AB -

The amateur (ham) radio community is a global community of over 3 million people who use and build radio equipment for communications, experimentation, and science. By definition, amateur radio is a volunteer service, with the operators required to hold government-issued licenses that are typically earned by passing knowledge tests covering radio regulations and practices, radio theory, and electromagnetic theory. In the United States, there are about 750,000 licensed hams, ranging in age from very young to very old, and ranging in experience from neophyte to people with advanced degrees in radio engineering and science. Amateur radio operators are licensed to transmit on bands spread across the radio frequency (RF) spectrum, from very low frequency (VLF) up to hundreds of gigahertz. The purpose of these communications range from mission-critical emergency and public service communications to social contacts to highly competitive contests and achievement award programs. Many of these communications rely on trans-ionospheric paths, and therefore are heavily influenced by conditions in near-Earth space, or space weather.
Amateurs today obtain space weather and propagation prediction information from sources such as the NOAA Space Weather Prediction Center (SWPC), spaceweather.com, the Voice of America Coverage Analysis Program (VOACAP), amateur radio propagation columnists (ARRL, RSGB, and CQ Magazine), and spaceweatherwoman.com (Dr. Tamitha Skov). In order to predict success for their communications efforts, hams often use parameters such as smoothed sunspot number, 10.7 cm wavelength solar flux proxy, and the planetary Kp and Ap indices as inputs to predict radio propagation performance. Traditionally, these predictions focus on the driving influence of space conditions and the sun’s output. However, frontier research in the space sciences community has revealed that for improved predictive success, much more information needs to be provided on neutral atmosphere dynamics from the lower atmosphere and its coupled effects on the ionosphere, and predictions need to be available at higher temporal and spatial resolution. Lower atmospheric influences include atmospheric gravity waves that can couple to traveling ionospheric disturbances that can dramatically alter radio propagation paths. Tropospheric phenomena such as temperature inversions and wind shear also affect VHF and UHF propagation. To be most useful, the ham community needs operational products that provide real time nowcasts and multi-day forecasts which predict how space weather through the whole atmosphere affects radio wave propagation on global scale and at all operational wavelengths.
To help with this effort, hams can provide data with unique spatial and temporal coverage back to the research and forecast community. The amateur radio community has already started this process with the creation of multiple global-scale, real-time propagation reporting systems such as the Weak Signal Propagation Reporting Network (WSPRNet), PSKReporter, and the Reverse Beacon Network (RBN). Studies by the Ham radio Science Citizen Investigation (HamSCI) have shown that data from these systems, if applied correctly, can effectively be used to study ionospheric space weather events. Experienced amateurs keep detailed records of verified point-to-point contacts and have extensive experience operating under a wide variety of geophysical conditions and locations, both of which can provide unique insights when shared with the professional research community. In this presentation, we will describe efforts led by the HamSCI collective to provide this research community feedback through active HamSCI community email lists and annual HamSCI workshops. We will also describe strategies with good initial success at amateur-professional collaboration, including a HamSCI-led amateur radio community - professional research community partnership to create a network of HamSCI Personal Space Weather Stations (PSWS), which will allow citizen scientists to make science-grade space weather observations from their own backyards.

JF - American Meteorological Society Annual Meeting PB - American Meteorological Society Annual Meeting CY - Boston, MA UR - https://ams.confex.com/ams/2020Annual/meetingapp.cgi/Paper/370904 ER - TY - CONF T1 - High Frequency Communications Response to Solar Activity in September 2017 as Observed by Amateur Radio Networks T2 - HamSCI Workshop 2019 Y1 - 2019 A1 - Nathaniel A. Frissell A1 - Joshua S. Vega A1 - Evan Markowitz A1 - Andrew J. Gerrard A1 - William D. Engelke A1 - Philip J. Erickson A1 - Ethan S. Miller A1 - R. Carl Luetzelschwab A1 - Jacob Bortnik AB -

Numerous solar flares and coronal mass ejection‐induced interplanetary shocks associated with solar active region AR12673 caused disturbances to terrestrial high‐frequency (HF, 3–30 MHz) radio communications from 4–14 September 2017. Simultaneously, Hurricanes Irma and Jose caused significant damage to the Caribbean Islands and parts of Florida. The coincidental timing of both the space weather activity and hurricanes was unfortunate, as HF radio was needed for emergency communications. This paper presents the response of HF amateur radio propagation as observed by the Reverse Beacon Network and the Weak Signal Propagation Reporting Network to the space weather events of that period. Distributed data coverage from these dense sources provided a unique mix of global and regional coverage of ionospheric response and recovery that revealed several features of storm time HF propagation dynamics. X‐class flares on 6, 7, and 10 September caused acute radio blackouts during the day in the Caribbean with recovery times of tens of minutes to hours, based on the decay time of the flare. A severe geomagnetic storm with Kpmax = 8+ and SYM‐Hmin = −146 nT occurring 7–10 September wiped out ionospheric communications first on 14 MHz and then on 7 MHz starting at ∼1200 UT 8 September. This storm, combined with affects from additional flare and geomagnetic activity, contributed to a significant suppression of effective HF propagation bands both globally and in the Caribbean for a period of 12 to 15 days.

JF - HamSCI Workshop 2019 PB - HamSCI CY - Cleveland, OH ER - TY - CONF T1 - IonTV: Using WWV Timing Reference Signals to Observe Ionospheric Variation T2 - Hamvention HamSCI Forum Y1 - 2019 A1 - Philip J. Erickson A1 - William Liles A1 - J. Dusenbury A1 - K.C. Kerby-Patel A1 - Ethan Miller A1 - Gary Bust A1 - Cathryn Mitchell AB -

For decades, an AM modulated time signal has been broadcast at multiple HF frequencies by the National Institute of Standards and Technology (NIST).  Shortwave radio stations WWV in Colorado and WWVH in Hawaii use these frequencies for the broad dissemination of accurate coordinated universal time information.  As the HF signal traverses the ionosphere, propagation effects ensue, and the high temporal precision of the original transmitted signal provides an attractive potential for wide-sense monitoring of ionospheric variations.  We present the results of an ongoing set of data collections and statistical analysis of the received variation in WWV timing signals aimed at extracting ionospheric propagation effects.  The work includes design of a software defined receiver (SDR) for processing the amplitude modulated dual sideband (AM-DSB) timing signal. By observing the time shift between consecutive seconds of the 10MHz WWV timing signal, reflected from the ionosphere, the change in the effective height of the ionosphere can be estimated.  Simultaneous measurements taken from different observation angles allow a more accurate sensing of ionospheric electron density variability as projected into refractive effects.  The project also has a goal of creating a straightforward and reliable way for hobbyists and citizen scientists to demodulate and process their own NIST timing data. We describe a sample analysis of several blocks of WWV received data, both on remote paths and locally through groundwave propagation near the Colorado transmit array, including simultaneous collects. To process the timing data, several approaches will be described, including a heterodyne SDR with a digital phase-locked-loop (PLL).  Carrier offset tracking using PLL techniques produce Doppler shifts that are associated with traveling ionospheric disturbances and inherent electron density variability.  Demodulation and amplitude/phase analysis of the 100 Hz subcarrier of WWV can also provide precise delta-time information on ionospheric propagation through examination of variability in arrival of the leading edge of 1 pulse-per-second ticks.  Results to date suggest that variation between consecutive second markers is a uniformly distributed Gaussian random variable with at least some of this variation due to ionospheric factors, although systematics must be addressed.

JF - Hamvention HamSCI Forum PB - Dayton Amateur Radio Association CY - Xenia, OH ER - TY - CONF T1 - IonTV: Using WWV Timing Reference Signals to Observe Ionospheric Variation T2 - HamSCI Workshop 2019 Y1 - 2019 A1 - Philip J. Erickson A1 - William Liles A1 - J. Dusenbury A1 - K.C. Kerby-Patel A1 - Ethan Miller A1 - Gary Bust A1 - Cathryn Mitchell AB -

For decades, an AM modulated time signal has been broadcast at multiple HF frequencies by the National Institute of Standards and Technology (NIST).  Shortwave radio stations WWV in Colorado and WWVH in Hawaii use these frequencies for the broad dissemination of accurate coordinated universal time information.  As the HF signal traverses the ionosphere, propagation effects ensue, and the high temporal precision of the original transmitted signal provides an attractive potential for wide-sense monitoring of ionospheric variations.  We present the results of an ongoing set of data collections and statistical analysis of the received variation in WWV timing signals aimed at extracting ionospheric propagation effects.  The work includes design of a software defined receiver (SDR) for processing the amplitude modulated dual sideband (AM-DSB) timing signal. By observing the time shift between consecutive seconds of the 10MHz WWV timing signal, reflected from the ionosphere, the change in the effective height of the ionosphere can be estimated.  Simultaneous measurements taken from different observation angles allow a more accurate sensing of ionospheric electron density variability as projected into refractive effects.  The project also has a goal of creating a straightforward and reliable way for hobbyists and citizen scientists to demodulate and process their own NIST timing data. We describe a sample analysis of several blocks of WWV received data, both on remote paths and locally through groundwave propagation near the Colorado transmit array, including simultaneous collects. To process the timing data, several approaches will be described, including a heterodyne SDR with a digital phase-locked-loop (PLL).  Carrier offset tracking using PLL techniques produce Doppler shifts that are associated with traveling ionospheric disturbances and inherent electron density variability.  Demodulation and amplitude/phase analysis of the 100 Hz subcarrier of WWV can also provide precise delta-time information on ionospheric propagation through examination of variability in arrival of the leading edge of 1 pulse-per-second ticks.  Results to date suggest that variation between consecutive second markers is a uniformly distributed Gaussian random variable with at least some of this variation due to ionospheric factors, although systematics must be addressed.

JF - HamSCI Workshop 2019 PB - HamSCI CY - Cleveland, OH ER - TY - CONF T1 - Large Scale Traveling Ionospheric Disturbances Observed using HamSCI Amateur Radio, SuperDARN, and GNSS TEC T2 - American Geophysical Union Fall Meeting Y1 - 2019 A1 - Nathaniel A. Frissell A1 - Diego F. Sanchez A1 - Evan Markowitz A1 - Gareth W. Perry A1 - William D. Engelke A1 - Anthea Coster A1 - Philip J. Erickson A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker AB -

Large Scale Traveling Ionospheric Disturbances (LSTIDs) are quasi-periodic variations in F region electron density with horizontal wavelengths > 1000 km and periods between 30 to 180 min. On 3 November 2017, LSTID signatures were detected in observations made by Reverse Beacon Network (RBN) and the Weak Signal Propagation Reporting Network (WSPRNet) for the first time. The RBN and WSPRNet are two large-scale High Frequency (HF, 3-30 MHz) amateur (ham) radio observing networks that provide data to the Ham Radio Science Citizen Investigation (HamSCI). The LSTIDs were observed on the 7 and 14 MHz amateur radio bands, and are detected by observing changes in average propagation path length with time. LSTID period lengthened from T ~ 1.5 hr at 12 UT to T ~ 2.25 hr by 21 UT. Simultaneous LSTID signatures were present in ham radio observations over the continental United States, the Atlantic Ocean, and Europe. LSTIDs observed with amateur radio were consistent with LSTIDs observed by the Blackstone SuperDARN HF radar and in differential GNSS Total Electron Content (TEC) measurements. GNSS TEC maps were used to estimate LSTID parameters: horizontal wavelength 1100 km, phase velocity 950 km/hr, period 70 min, and propagation azimuth 135°. The LSTID signatures were observed throughout the day following ~800 nT surges in the Auroral Electrojet (AE) index at 00 and 12 UT. We will discuss potential generation hypotheses for the observed LSTIDs, including atmospheric gravity wave (AGW) sources triggered by auroral electrojet intensifications and associated Joule heating.

JF - American Geophysical Union Fall Meeting PB - American Geophysical Union CY - San Francisco, CA UR - https://agu.confex.com/agu/fm19/meetingapp.cgi/Paper/581488 ER - TY - CONF T1 - A Low-Cost Citizen Science HF Doppler Receiver for Measuring Ionospheric Variability T2 - American Geophysical Union Fall Meeting Y1 - 2019 A1 - Kristina Collins A1 - David Kazdan A1 - John Gibbons A1 - Aidan Montare A1 - Skylar Dannhoff A1 - Philip J. Erickson A1 - Nathaniel A. Frissell AB -

Advancement in understanding short term and small spatial scale ionospheric variability requires global high time and spatial resolution measurements. Professional ionospheric sounding networks are extensive and capable, yet more measurements are still needed due to the strongly magnetized nature and large extent of the ionosphere. High Frequency (HF, 3-30 MHz) radio signals are refracted by the ionosphere, and therefore are modulated by processes such as traveling ionospheric disturbances (TIDs) and geomagnetic storms. By measuring the amplitude and Doppler shift of trans-ionospheric HF signals, it is possible to detect signatures of ionospheric absorption and changes in propagation path length. We present a design for a low-cost citizen science HF multi-band receiver that measures the amplitude and Doppler shift of reference signals of opportunity from the US National Institute of Standards and Technology station WWV and the Canadian Institute for National Measurement Standards station CHU. The receiver will make 1 s cadence measurements on nine HF beacon frequencies and subsequently upload the results to a central server for scientific analysis. The local user will be able to review data daily, both locally and in aggregate on a web server, and participate in discussion of the ionospheric measurements. This receiver forms one component of the low-cost version of the Ham Radio Science Citizen Investigation (HamSCI) Personal Space Weather Station (PSWS), and is designed with the intention of distribution to hundreds to thousands of citizen science observers. Preliminary results from the prototype receiver will be presented.

JF - American Geophysical Union Fall Meeting PB - American Geophysical Union CY - San Francisco, CA UR - https://agu.confex.com/agu/fm19/meetingapp.cgi/Paper/602677 ER - TY - CONF T1 - PSWS Science Requirements Panel Discussion (Panel) T2 - HamSCI Workshop 2019 Y1 - 2019 A1 - John Ackermann A1 - Scotty Cowling A1 - Philip J. Erickson A1 - Nathaniel A. Frissell A1 - Hyomin Kim A1 - William Liles A1 - Thomas McDermott A1 - Ward Silver AB -

Moderator: Ward Silver, N0AX

  1. Phil Erickson, W1PJE, MIT Haystack Observatory, Radio, Ionospheric, & Magnetospheric Science
  2. Nathaniel Frissell, W2NAF, NJIT, Radio, Ionospheric, & Magnetospheric Science
  3. Hyomin Kim, KD2MCR, NJIT, Magnetospheric Physics
  4. Bill Liles, NQ6Z, VLF Science
  5. John Ackermann, N8UR, TAPR, Radio Engineering
  6. Scotty Cowling, WA2DFI, TAPR, Radio Engineering
  7. Tom McDermott, N5EG, TAPR, Radio Engineering
JF - HamSCI Workshop 2019 PB - HamSCI CY - Cleveland, OH ER - TY - CONF T1 - Sounding the Ionosphere with Signals of Opportunity in the High-Frequency (HF) Band T2 - HamSCI Workshop 2019 Y1 - 2019 A1 - Ethan S. Miller A1 - Gary S. Bust A1 - Gareth W. Perry A1 - Stephen R. Kaeppler A1 - Juha Vierinen A1 - Nathaniel A. Frissell A1 - A. A. Knuth A1 - Philip J. Erickson A1 - Romina Nikoukar A1 - Alexander T. Chartier A1 - P. Santos A1 - C. Brum A1 - J. T. Fentzke A1 - T. R. Hanley A1 - Andrew J. Gerrard AB -

The explosion of commercial off-the-shelf (COTS) education- and consumer-grade hardware supporting software-defined radio (SDR) over the past two decades has revolutionized many aspects of radio science, bringing the cost and calibration of traditionally complex receiver hardware within the grasp of even advanced amateur experimenters. Transmission has now become the limiter of access in many cases, particularly through spectrum management and licensing considerations. Fortunately, several classes of signals endemic to the HF band lend themselves to processing for ionospheric characteristics: time and frequency standard broadcasters, surface-wave oceanographic radars, amateur radio transmissions, and ionospheric sounders.

This presentation is a tour of these signals of opportunity and techniques for collecting and processing them into ionospheric characteristics, with emphasis on distributed receivers collecting on a small number (four or fewer) of coherent channels. Receiving techniques will be discussed for near-vertical (“quasi-vertical”) incidence skywave (NVIS or QVI), long-distance oblique soundings, and transionospheric sounding. Soundings will be demonstrated from space-based, ground-based, and maritime platforms.

Binary, Doppler, delay, cone angle of arrival, and polarization observations will be exploited, depending on the signal type and capability of the collector. Each of these techniques conveys different, but not always “orthogonal,” information about the ionospheric skywave channel. The information content of each datum will be discussed with respect to the implications for inverting the local or regional ionosphere from the observations. More importantly than inverting the full ionosphere, some of these techniques are sensitive indicators of ionospheric irregularities, structures, and instabilities, that might otherwise be difficult to study due to limited geographic coverage with larger, more exquisite instrumentation.

JF - HamSCI Workshop 2019 PB - HamSCI CY - Cleveland, OH ER - TY - CONF T1 - Upper Level Lows and Six Meter 50 Mhz Sporadic E T2 - Dayton Hamvention Y1 - 2017 A1 - Joseph A. Dzekevich A1 - Philip J. Erickson AB -

Amateur radio is used to explore possible correlations between weather storm systems and sporadic E clouds to see if they are collocated. While some of the main causes of sporadic E propagation are wind shear, meteor strikes and upper atmospheric tides (ultimately coming from solar EUV energy inputs), radio operators have noticed that sporadic E propagation is also changed significantly by hurricanes and storms.  Specific cases where K1YOW used amateur radio to investigate the effects of low pressure weather storms on the formation and/or enhancement of 6 meter sporadic E clouds are presented. DX Maps and earth wide weather model charts combined with operations on 6 meters are used to examine possible correlations between the location of the sporadic E clouds and the low pressure weather storm systems.  Initial findings show a high degree of correlation when magnetic field strength is taken into consideration.

JF - Dayton Hamvention CY - Xenia, OH ER -